Assertion (A): In an isolated system, the heat transfer $\partial$Q and the work transfer $\partial$W are always zero.
Reason (R): In an isolated system; the entropy always remains constants.
a) Both A and R are individually true and R is the correct explanation of A
b) Both A and R are individually true but R is not the correct explanation of A
c) A is true but R is false
d) A is false but R is true